Quality concerns with the 2018 corn harvest – Is DON a concern for veal production?

The situation

Ontario is facing a severe outbreak of in DON in corn this fall. Deoxynivalenol (DON) is a vomitoxin which is a type of mycotoxin (toxin produced by mould) produced by fungus that infects grains, including corn. Due to the very wet summer and harvest season, corn in Ontario has been found to have unusually high levels of DON, with corn from some areas of the province more affected than others.
Most years, crops have about three parts per million (ppm) of vomitoxin. This year, routine testing has found levels up to 37 ppm. An October 2018 OMAFRA survey found more than 25% of samples had over 5 ppm.
A. Less than 0.5 ppm
B. 0.5 – 2 ppm
C. Greater than 2 ppm

Mycotoxin research in veal production

In the late 2000’s the legacy association the Ontario Veal Association studied the effects of DON on veal cattle on growth, health, and carcass quality at nine ppm (mg/kg) DON. The study found that calves can handle diets of 10.27 ppm (mg/kg) DON. In fact, veal cattle in the study had the same dry matter intake, and those with DON contaminated diets tended to have a better average daily gain and better feed efficiency. Final body weights and total weight gain were no different between contaminated and uncontaminated diets. No effect on carcass traits was found. The study indicated that veal cattle can handle a moderate amount of DON in their diet. Authors of this study called for follow up research to verify the results, examine potential meat residues, and investigate effects of different levels of DON.
It is important to note that there are few studies on this issue, especially in grain-fed veal production, and that concentrations and combinations of mycotoxins in reality may differ from the concentrations and combinations tested in research settings. For this reason, saying with certainty how a contaminated corn product may impact your veal cattle is impossible, and caution is warranted.
The first sign of a problem will be cattle going off-feed. If your cattle go off-feed, work with both your veterinarian and your nutritionist and consider DON levels a potential cause. Identifying the problem and quickly adjusting the diet is key to minimizing lost growth.
When consulting with James Byrne, Beef Cattle Specialist with Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) stated;
“Beef cattle are very resistant to DON, unlike other species such as pigs. The Canadian Food Inspection Agency (CFIA) sets a maximum DON level in the total diet of five ppm for beef cattle four months and older and that DON infected grains not exceed 50% of the diet. The United States Food and Drug Administration set this level at 10 ppm of the total diet. It’s important to note that these limits are for the total diet. Feeding forages significantly reduces the concentration of DON in the total diet.
The [Beef Cattle Research Council] (BCRC) in their Feed Grains & Feed Efficiency Report 2017 point to research work where “Growing-finishing cattle can tolerate much higher levels of DON in their diet without going off-feed. In a University of Minnesota feeding trial (1993-94) steers were fed rations containing up to 18 ppm DON of the total diet through the finishing phase with no effect on gain, feed intake or feed efficiency. An [North Dakota State University] (NDSU) trial (1993-94) fed up to 9 ppm DON during the growing phase and up to 12 ppm during the finishing phase with no effects on performance.”

How can veal producers make use of contaminated corn?

The research Byrnes refers to substantiates the initial research of the Ontario Veal Association in grain-fed veal cattle. Pay close attention to veal cattle being fed questionable corn as there is always a risk. A back-up plan should be in place in the event the cattle cannot handle corn with high levels of DON and experience a setback.
It is advisable to work closely with a feed nutritionist, especially this year, regardless of if you are feeding homegrown or purchased corn to ensure diets are designed with DON levels in mind.
Byrne also noted that the main strategies used by the feed industry for mitigating the effect of DON are (a) blending contaminated grains with clean grains (diluting the mycotoxin concentration to within acceptable limits) or (b) add approved ingredients, such as anti-caking agents or yeast products (toxin binders).

What about unweaned calves?

Calves less than four months are unlikely to be affected by this DON issue as their grain intake as a percentage of total diet is typically small.
Are there human health effects?
Feeding mouldy feed can have negative human health effects by creating respiratory disease when spores are breathed in from harvesting, handling, feeding, or working around mouldy feed. Symptoms of exposure can include burning eyes, throat, and chest as well as irritating cough and fever. Be aware of changes in health of yourself and others in your operation and seek medical advice if needed. Inform your doctor that you have worked with potentially contaminated feed.


Any farmer who discovers DON in their crop is encouraged to call Agricorp as soon as possible at 1-888-247-4999. Agricorp can discuss the best practices for handling, sorting, and if necessary, destroying high DON corn, and review the coverage available to farmers experiencing losses due to DON.
For those who have been impacted by this issue, this is an especially stressful time. If you need to talk to someone, please call 211 (Canadian Mental Health Line), or 1-866-531-2600 (Ontario Mental Health Helpline) to speak to someone. Do More Ag also provides resources for mental health and well-being.

Further reading